1. Field of the Invention
The present invention generally relates to electronic apparatus and, in a preferred embodiment thereof, more particularly relates to keyboard and cursor control apparatus for computers.
2. Description of Related Art
In a commonly utilized computer keyboard of conventional construction, utilized in both portable computers and desktop computer systems, a series of manually depressible key cap members are supported above a multi-layer membrane switch structure for downward movement, through a key stroke distance, toward segmented switch structures disposed beneath each key member. Also underlying the key members are key return spring members, such as elastomeric dome structures, which function to resiliently bias the keys to their upwardly extended pre-typing positions. While this multi-layer signal pad and electrical switch structure has proven to be satisfactory from a functional standpoint, it nevertheless has several disadvantages such as structural and fabricational complexity, bulk, and an increased potential for fatigue and other mechanical and electrical wear and failure problems.
In conjunction with these conventionally constructed portable and desktop computer keyboard structures, a variety of display screen cursor control systems have previously been utilized on or adjacent the keyboard. These cursor control devices include mice, trackballs, touchpads and pointing sticks.
The computer mouse is basically a small housing which has a ball on its underside that is rolled by the computer user along a horizontal support surface adjacent the keyboard in response to hand movement of the mouse housing parallel to the support surface. The sense and speed of the rotation of the mouse ball is monitored and appropriately converted to a positional output signal used to correspondingly reposition the cursor on the computer. The mouse housing typically has at least one "pick" button thereon which may be depressed to select an icon to which the cursor has been moved, or simply to select a desired screen location.
A track ball is basically an inverted mouse with the ball facing upwardly for direct manipulation by the computer user's fingers. The track ball is typically mounted on the base housing of a portable computer adjacent one or more "pick" buttons associated with the ball.
A touchpad typically has a small, generally planar rectangular surface along which the user runs his finger in the desired direction of cursor movement. A sensing structure beneath the user-engaged surface converts his finger movements to appropriate cursor movement signals. As in the case of the track ball and mouse, the touchpad is typically placed adjacent one or more manually depressible "pick" buttons.
A pointing stick is typically placed among and projects upwardly beyond a group of keyboard key cap members --typically in a generally central location of the keyboard between the user's index fingers in their "home" typing positions. Either index finger may be used to tilt the vertically oriented pointing stick in the desired direction of cursor movement, with a pressure sensing base portion of the pointing stick structure detecting the rocking movement of the stick and transforming the detected stick into corresponding cursor movement signals.
A recent potential addition to these types of cursor control devices, a two dimensional optical digitizer device, is illustrated and described in pending U.S. application Ser. No. 08/486,310, filed on Jun. 7, 1995, and pending U.S. application Ser. No. 08/651,881, filed on Jun. 4, 1996, each of such pending applications being assigned to the same assignee as this application. These digitizer devices utilize a single source of light to form a generally planar two dimensional light pattern disposed over and generally parallel to a computer keyboard. A finger placed in the light pattern interrupts a corresponding portion thereof, with the interruption location being sensed and used to transmit positional information to the display screen.
As in the case of their associated keyboard structures, various problems, limitations and disadvantages are typically associated with these previously proposed types of cursor control devices and systems. It is to these keyboard and cursor control apparatus problems, limitations and disadvantages that the present invention is directed.
For example, with respect to the cursor control devices and systems, the computer mouse requires a substantial amount of unobstructed desktop space adjacent the keyboard to be moved around in. Also, many computer mice are configured for right hand use, making them awkward for the left-handed user. The trackball is typically integrated into the system keyboard area in a fixed location which is usually a comprise based on where there is space in the system. Accordingly, the trackball can often be somewhat awkward to use.
The touchpad, like the trackball, is typically integrated into a fixed area of the system keyboard structure. Additionally, the touchpad typically has a relatively small surface area along which the user's finger can be moved to correspondingly move the display screen cursor. Accordingly, the touchpad tends to be rather inconvenient to use when long cursor movements are required.
The pointing stick is the smallest of the conventionally utilized cursor positioning devices and thus may be very compactly located on the keyboard structure. However, the small size of this device makes it somewhat difficult for some users to properly engage and use. Additionally, since the pointing stick is usually centrally located in the keyboard it usually must be separated a substantial distance from its associated selection buttons. This, too, is often considered undesirable by computer users. Moreover, due to the "rocking" motion that must be imparted to the pointing stick to operate it, the use of the stick is considered by many users to be at least to some degree counterintuitive.
The optical digitizers mentioned above require for the generation and maintenance of their optical fields above and generally parallel to the keyboard a variety of reflector, interceptor and light generating members mounted in exposed orientations on the keyboard. Additionally, their optical fields as a practical matter are limited to two dimensions, thereby limiting their object recognition capabilities.
In view of the foregoing it can be seen that it would be desirable to provide for a computer improved keyboard and cursor control apparatus which eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages typically associated with previously proposed keyboard and cursor control apparatus.